Often applied in process automation technology are field devices, which serve for registering and/or influencing process variables. Examples of such field devices are fill level measuring devices, mass flow measuring devices, pressure- and temperature measuring devices, etc., which as sensors register the corresponding process variables, fill level, flow, pressure and temperature, respectively.
Referred to as field devices are, in principle, all devices, which are applied near to the process and deliver, or process, process relevant information.
A large number of such field devices are produced and sold by the firm, Endress+Hauser.
In the case of many measurement applications, a goal is to convert a time signal into a corresponding frequency spectrum, in order to be able to determine the frequency components contained in the frequency spectrum.
For example, for determining the fill level in a container or tank, a fill-level measuring device can be used, which works according to the FMCW radar principle. In such case, a frequency modulated radar transmission signal is transmitted and reflected on the surface of the liquid or the bulk good back to the fill-level measuring device. As a result of the measuring, one obtains a discrete time signal, which contains one or more frequency components. Based on the frequency components contained in the discrete time signal, the fill level in the container or tank can be derived. In such case, the accuracy, with which the fill level can be determined, depends on the accuracy, with which the frequency components contained in the time signal can be ascertained